This invention relates to electrical connectors and, more particularly, to hermetically sealed electrical connectors for use in passing electrical conductors through a bulkhead while simultaneously isolating high pressure on one side of the bulkhead from low pressure on the other side of the bulkhead and methods of making the same.
Various structures have been developed as electrical connectors to allow ready attachment and detachment of wires between electrical devices. Many electrical connectors include a plug and a receptacle. The plug includes one or more electrically conductive male contacts or pins, and the receptacle includes a like number of female electrically conductive contacts. Either the male contacts, the female contacts, or both are permanently electrically connected to wires or leads. Either the plug or the receptacle is mounted in a wall or secure structure, such as a bulkhead, although in some instances both the plug and the receptacle will be connected to one another independently of any other structure. Electrical connection is easily achieved by pushing the male contacts on the plug into the receptacle (or vice versa), and disconnection is achieved by pulling the plug out of the receptacle. Such components are often mated with other components such as socket blocks or sealed connector boot assemblies. Where the connector is situated within a bulkhead, the connector is essentially the main component and attachment to each of the exposed ends of the conductors of the connector could be accomplished either by direct and permanent connection to egress leads or by removable connections as described above.
Generally the electrically conductive contacts of both the plug and the receptacle are supported in a dimensionally stable, electrically insulative material surrounded by a metallic housing or similar rigid structure. This insulator electrically isolates the various contacts and further maintains alignment of the contacts for ready connection and disconnection and to maintain electrical isolation from the housing and the bulkhead, if any. Metal housings are often used to provide greater support for the connector, and are particularly useful in settings where high forces will be encountered by the connector. Notwithstanding the advantages of using housings, such structures can have significant drawbacks, including the cost of making the housings and incorporating the housings into the connector.
Moreover, in certain settings it is desired that either the plug or receptacle be xe2x80x9chermeticallyxe2x80x9d sealed, i.e., sealed so as to prevent egress of fluids across a boundary created by the seal. Hermetically sealed connectors are particularly useful when it is necessary to maintain a controlled environment on one or both sides of the connector, and specifically where the integrity of electrical power or an electrical signal must be maintained between a region of relatively high pressure from a region of relatively low pressure. Hermetic connectors have particularly great utility in the field of downhole well tools used for subterranean drilling operations, where temperatures exceed 400 degrees Fahrenheit and pressures can reach above 25,000 pounds per square inch. In such settings, various electronic components are housed within the downhole well tools and such electronics generally are designed to operate at atmospheric pressure, thereby requiring effective isolation between the high pressures of the ambient environment within the well and the pressure within electronics modules. Additionally, it is generally required that electrical leads pass from within the sealed well, at high pressure, to the ambient conditions above ground to provide for control and monitoring within the well. Accordingly, for both conditions, hermetic connectors are essential to the functioning of downhole well tools.
The use of a housing to support an electrical connector in such a high-pressure, harsh environment presents the additional problem of sealing the interface between not only the connector and the bulkhead, but also between the insulator and the housing. Where down time due to a failure of a seal can be extremely costly, elimination of a possible leak path is a significant advance in the art. Thus, elimination of the housing, while maintaining the structural support provided by the housing, would be a significant advance in the art.
The connector of the present invention eliminates the housing and the problems associated therewith and provides an electrical connector that also serves to seal a relatively low pressure from real or potential exposure to a relatively high pressure. It can withstand extremely high differential pressures, up to at least 25,000 pounds per square inch, while preventing pressure or electrical leakage. It can be used in any environment wherein high pressure differential exists and there is a need to protect electronics or other electrical or mechanical assemblies from exposure to undesirable higher or lower pressures than the those at which they were designed to operate, and where electrical power or signals must be passed across the boundary between high and low pressure.
Briefly stated, the present invention is directed to
A hermetic pressure connector for providing a pressure-tight, electrically-conductive connection through a hole in a bulkhead. The connector includes a transverse support member having a passage therethrough. A conductor pin extends through the passage. A molded body surrounds at least a central portion of the pin and electrically insulates the transverse support member from the pin and the pin from the bulkhead. The molded body is directly sealingly engaged to the conductor pin.
In another aspect, the present invention is a method of making a hermetic pressure connector for providing a pressure-tight, electrically-conductive connection through a hole in a bulkhead. The method includes placing a conductor pin into a passage in a transverse support member and positioning the conductor pin and transverse support member within an injection mold having the desired finished shape of the molded body. The positioning is such that the conductor pin is spaced from the transverse support member. The method also includes injecting a polymeric material into the injection mold for creating a molded body which surrounds the conductor pin and electrically insulates the conductor pin from the transverse support member. The molded body, conductor pin and transverse support member are removed from the injection mold.